I have a problem with my M800. I bought it from a shop in Guangzhou named V.Star and it used to work very good until I activate a widget for Powersave. I select a powersave option for screen and everything goes black. The tablet boot up normal, android logo appear and when finish to boot the screen goes black. I can hear sound if I touch the screen but I have no Ideea how to make it work. Do you think installing firmaware can solve this? Or maybe you have a better advice. Thanks in advance.